Optimizing synchronization of audio and network tasks in voice over packet switched networks

ABSTRACT

A user equipment device (UE) comprises physical layer circuitry configured to transmit and receive radio frequency electrical signals with one or more nodes of a radio access network, an audio subsystem configured to generate frames of audio data, and processing circuitry. The processing circuitry is configured to calculate a time delay from generation of an audio data frame by the audio subsystem of the UE device to transmission of an audio data packet by the physical layer circuitry during a voice call, and decrease the time delay to a delay value that preserves a specified minimum time for delivery of the generated audio data frame to the physical layer circuitry to meet a scheduled transmission time of the audio data packet.

TECHNICAL FIELD

Embodiments pertain to transmitting packetized voice data using radioaccess networks. Some embodiments relate to voice over internet protocol(VoIP) or voice over long term evolution protocol (VoLTE).

BACKGROUND

Radio access networks are used for delivering voice communications touser equipment such as a cellular telephone or a smart phone. Some radionetworks are packet switched networks and packetize the voice data whenit is sent over the network. Packetizing voice information and routingpacketized voice data can introduce latency into voice communicationsthat impacts the quality of the communications provided by the network.Latency refers to the time between collecting voice data during a phonecall to when the voice data reaches the destination. This latency canlead to delay and can impact the conversation quality of the voice call.Thus, there are general needs for devices, systems and methods thatprovide a robust protocol for communication with user equipment and yetminimize delay in end-to-end voice communications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a portion of an end-to-end networkarchitecture of an LTE network with various components of the network inaccordance with some embodiments;

FIG. 2 shows a flow diagram of an example of a method of reducing delayin the uplink of voice information in a radio access network inaccordance with some embodiments;

FIGS. 3A and 3B illustrate an example of determining and reducing thedelay in the uplink of voice information in a radio access network inaccordance with some embodiments;

FIG. 4 shows a functional block diagram of an example of a UE inaccordance with some embodiments;

FIG. 5 illustrates another example of reducing delay in the uplink ofvoice information in radio access network in accordance with someembodiments; and

FIG. 6 illustrates still another example of reducing delay in the uplinkof voice information in radio access network in accordance with someembodiments.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

FIG. 1 shows an example of a portion of an end-to-end networkarchitecture of an LTE network with various components of the network inaccordance with some embodiments. The network 100 comprises a radioaccess network (RAN) (e.g., as depicted, the E-UTRAN or evolveduniversal terrestrial radio access network) 100 and the core network 120(e.g., shown as an evolved packet core (EPC)) coupled together throughan S1 interface 115. For convenience and brevity, only a portion of thecore network 120, as well as the RAN 100, is shown in the example.

The core network 120 includes mobility management entity (MME) 122,serving gateway (serving GW) 124, and packet data network gateway (PDNGW) 126. The RAN includes enhanced node B's (eNBs) 104 (which mayoperate as base stations) for communicating with user equipment (UE)102. The eNBs 104 may include macro eNBs and low power (LP) eNBs.

The MME is similar in function to the control plane of legacy ServingGPRS Support Nodes (SGSN). The MME manages mobility aspects in accesssuch as gateway selection and tracking area list management. The servingGW 124 terminates the interface toward the RAN 100, and routes datapackets between the RAN 100 and the core network 120. In addition, itmay be a local mobility anchor point for inter-eNB handovers and alsomay provide an anchor for inter-3GPP mobility. Other responsibilitiesmay include lawful intercept, charging, and some policy enforcement. Theserving GW 124 and the MME 122 may be implemented in one physical nodeor separate physical nodes. The PDN GW 126 terminates an SGi interfacetoward the packet data network (PDN). The PDN GW 126 routes data packetsbetween the EPC 120 and the external PDN, and may be a key node forpolicy enforcement and charging data collection. It may also provide ananchor point for mobility with non-LTE accesses. The external PDN can beany kind of IP network, as well as an IP Multimedia Subsystem (IMS)domain. The PDN GW 126 and the serving GW 124 may be implemented in onephysical node or separated physical nodes.

The eNBs 104 (macro and micro) terminate the air interface protocol andmay be the first point of contact for a UE 102. In some embodiments, aneNB 104 may fulfill various logical functions for the RAN 100 includingbut not limited to RNC (radio network controller functions) such asradio bearer management, uplink and downlink dynamic radio resourcemanagement and data packet scheduling, and mobility management. Inaccordance with embodiments, UEs 102 may be configured to communicateOFDM communication signals with an eNB 104 over a multicarriercommunication channel in accordance with an OFDMA communicationtechnique. The OFDM signals may comprise a plurality of orthogonalsubcarriers.

The S1 interface 115 is the interface that separates the RAN 100 and theEPC 120. It is split into two parts: the S1-U, which carries trafficdata between the eNBs 104 and the serving GW 124, and the S1-MME, whichis a signaling interface between the eNBs 104 and the MME 122. The X2interface is the interface between eNBs 104. The X2 interface comprisestwo parts, the X2-C and X2-U. The X2-C is the control plane interfacebetween the eNBs 104, while the X2-U is the user plane interface betweenthe eNBs 104.

With cellular networks, LP cells are typically used to extend coverageto indoor areas where outdoor signals do not reach well, or to addnetwork capacity in areas with very dense phone usage, such as trainstations. As used herein, the term low power (LP) eNB refers to anysuitable relatively low power eNB for implementing a narrower cell(narrower than a macro cell) such as a femtocell, a picocell, or amicrocell. Femtocell eNBs are typically provided by a mobile networkoperator to its residential or enterprise customers. A femtocell istypically the size of a residential gateway or smaller, and generallyconnects to the user's broadband line. Once plugged in, the femtocellconnects to the mobile operator's mobile network and provides extracoverage in a range of typically 30 to 50 meters for residentialfemtocells. Thus, a LP eNB might be a femtocell eNB since it is coupledthrough the PDN GW 126. Similarly, a picocell is a wirelesscommunication system typically covering a small area, such asin-building (offices, shopping malls, train stations, etc.), or morerecently in-aircraft. A picocell eNB can generally connect through theX2 link to another eNB such as a macro eNB through its base stationcontroller (BSC) functionality. Thus, LP eNB may be implemented with apicocell eNB since it is coupled to a macro eNB via an X2 interface.Picocell eNBs or other LP eNBs may incorporate some or all functionalityof a macro eNB. In some cases, this may be referred to as an accesspoint base station or enterprise femtocell.

In some embodiments, a downlink resource grid may be used for downlinktransmissions from an eNB to a UE. The grid may be a time-frequencygrid, called a resource grid, which is the physical resource in thedownlink in each slot. Such a time-frequency plane representation is acommon practice for OFDM systems, which makes it intuitive for radioresource allocation. Each column and each row of the resource gridcorrespond to one OFDM symbol and one OFDM subcarrier, respectively. Theduration of the resource grid in the time domain corresponds to one slotin a radio frame. The smallest time-frequency unit in a resource grid isdenoted as a resource element. Each resource grid comprises a number ofresource blocks, which describe the mapping of certain physical channelsto resource elements. Each resource block comprises a collection ofresource elements and in the frequency domain, this represents thesmallest quanta of resources that currently can be allocated. There areseveral different physical downlink channels that are conveyed usingsuch resource blocks. Two of these physical downlink channels are thephysical downlink shared channel and the physical down link controlchannel.

The physical downlink shared channel (PDSCH) carries user data andhigher-layer signaling to a UE 102 (FIG. 1). The physical downlinkcontrol channel (PDCCH) carries information about the transport formatand resource allocations related to the PDSCH channel, among otherthings. It also informs the UE about the transport format, resourceallocation, and H-ARQ information related to the uplink shared channel.Typically, downlink scheduling (assigning control and shared channelresource blocks to UEs within a cell) is performed at the eNB based onchannel quality information fed back from the UEs to the eNB, and thenthe downlink resource assignment information is sent to a UE on thecontrol channel (PDCCH) used for (assigned to) the UE.

As explained previously, forming voice information into packetized dataand routing the packetized voice data over a network can introducelatency into voice communications. The inventors have recognized thatthe uplink of voice information in the UE can have a significant impacton the latency. For example, lack of synchronization between the audioprocessing tasks and the transmission scheduling tasks of the UE canintroduce delay into end-to-end voice communications. Improving thissynchronization can reduce latency in voice communication.

FIG. 2 shows a flow diagram of an example of a method 200 of reducingdelay in the uplink of voice information in a radio access network. At205, a time delay is calculated. The time delay includes the timeduration from the generation of an audio data frame by an audiosubsystem of the UE device to transmission of an audio data packet bythe physical layer of the UE device during a voice call.

FIG. 3A illustrates an example of determining the time delay. At 305,the audio subsystem of a UE has generated audio data from a voice call.The UE may generate the audio data by digitizing voice information aspulse code modulation (PCM) samples. At 305, the voice call audio datais encoded and formed into one or more packets, such as according to areal time protocol (RTP) for example. In the example shown in FIG. 3,there is a 20 millisecond (20 ms) time period between transmitting thepackets and the audio data frames are available 12 ms ahead of the nextpacket transmit time. Thus, there is a 12 ms time delay from the timethat the audio data frame is generated to the time that the audio datapacket begins to be transmitted. The example in FIG. 3A shows that thetime period between audio data packets remains the same for a series of100 audio data packets and the time delay remains 12 ms for the 100audio data packets. The time delay can be calculated or measured anytime during the call including the beginning or initiation of the calland while the call is active and ongoing.

Referring to FIG. 2 at 210, the time delay is decreased to a delay valuethat preserves a specified minimum time for delivery of the generatedthe audio data frame to the physical layer to meet a scheduledtransmission time of the audio data packet. This specified minimum timecan be referred to as a watermark. FIG. 3B illustrates an example ofdecreasing the time delay. The generation of the audio data and the timefor transmitting the audio data are synchronized to occur closertogether. The time delay or wait time is the time from delivery of theaudio data frame to the earliest forthcoming uplink grant. In theexample, the time delay is reduced to 2 ms. The time between productionof audio data packets and consumption of the packets is made as small aspossible to minimize end-to-end latency. A small non-zero time delay ismaintained as the watermark to avoid the situation where the audio datagenerating happens later than the scheduled time for transmission.

FIG. 4 illustrates a functional block diagram of a UE in accordance withsome embodiments. The UE 400 may be suitable for use as any one or moreof the UEs 102 illustrated in FIG. 1. The UE 400 may include physicallayer (PHY) circuitry 402 for transmitting and receiving radio frequencyelectrical signals to and from one or more nodes of a radio accessnetwork such as eNBs 104 (FIG. 1) using one or more antennas 401. ThePHY circuitry 402 may include circuitry for modulation/demodulation,upconversion/downconversion, filtering, amplification, etc. UE 400 mayalso include medium access control layer (MAC) circuitry 404 forcontrolling access to the wireless medium and to configure frames orpackets for communicating over the wireless medium. UE 400 may alsoinclude processing circuitry 406 and memory 408 arranged to configurethe various elements of the UE to perform the operations describedherein. The memory 408 may be used to store information for configuringthe processing circuitry 406 to perform the operations. The UE mayinclude an audio subsystem 409. The audio subsystem may include an audiocodec to digitize voice information and to receive and decode audioinformation. The audio subsystem 409 generates frames of audio datausing the digitized voice information produced by the audio codec.

In some embodiments, the UE 400 may be part of a portable wirelesscommunication device, such as a personal digital assistant (PDA), alaptop or portable computer with wireless communication capability, aweb tablet, a wireless telephone, a smartphone, a wireless headset, apager, an instant messaging device, a digital camera, an access point, atelevision, a medical device (e.g., a heart rate monitor, a bloodpressure monitor, etc.), or other device that may receive and/ortransmit information wirelessly. In some embodiments, the UE 400 mayinclude one or more of a keyboard, a display, a non-volatile memoryport, multiple antennas, a graphics processor, an application processor,speakers, and other mobile device elements. The display may be an LCDscreen including a touch screen.

The one or more antennas 401 utilized by the UE 400 may comprise one ormore directional or omnidirectional antennas, including, for example,dipole antennas, monopole antennas, patch antennas, loop antennas,microstrip antennas or other types of antennas suitable for transmissionof RF signals. In some embodiments, instead of two or more antennas, asingle antenna with multiple apertures may be used. In theseembodiments, each aperture may be considered a separate antenna. In somemultiple-input multiple-output (MIMO) embodiments, the antennas may beeffectively separated to take advantage of spatial diversity and thedifferent channel characteristics that may result between each ofantennas and the antennas of a transmitting station. In some MIMOembodiments, the antennas may be separated by up to 1/10 of a wavelengthor more.

Although the UE 400 is illustrated as having several separate functionalelements, one or more of the functional elements may be combined and maybe implemented by combinations of software-configured elements, such asprocessing elements including digital signal processors (DSPs), and/orother hardware elements. For example, some elements may comprise one ormore microprocessors, DSPs, application specific integrated circuits(ASICs), radio-frequency integrated circuits (RFICs), and combinationsof various hardware and logic circuitry for performing at least thefunctions described herein. In some embodiments, the functional elementsmay refer to one or more processes operating on one or more processingelements.

Embodiments may be implemented in one or a combination of hardware,firmware and software. Embodiments may also be implemented asinstructions stored on a computer-readable storage medium, which may beread and executed by at least one processor to perform the operationsdescribed herein. A computer-readable storage medium may include anynon-transitory mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a computer-readable storagemedium may include read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memorydevices, and other storage devices and media. In these embodiments, oneor more processors may be configured with the instructions to performthe operations described herein.

In some embodiments, the UE 400 may be configured to receive OFDMcommunication signals over a multicarrier communication channel inaccordance with an OFDMA communication technique. The OFDM signals maycomprise a plurality of orthogonal subcarriers. In some broadbandmulticarrier embodiments, eNBs may be part of a broadband wirelessaccess (BWA) network communication network, such as a WorldwideInteroperability for Microwave Access (WiMAX) communication network or a3rd Generation Partnership Project (3GPP) Universal Terrestrial RadioAccess Network (UTRAN) Long-Term-Evolution (LTE) or aLong-Term-Evolution (LTE) communication network or a high speeddownlink/uplink access (HSDPA/HSUPA) communication network, although thescope of the invention is not limited in this respect.

The processing circuitry 406 is configured (e.g., by one or acombination of hardware, firmware and software) to calculate a timedelay from generation of an audio data frame by the audio subsystem 409to transmission of an audio data packet by the physical layer circuitry402 during a voice call, including the beginning or initiation of thevoice and while the voice call is ongoing. The processing circuitry 406decreases the time delay to a delay value that preserves a specifiedminimum time for delivery of the generated audio data frame to thephysical layer circuitry to meet a scheduled transmission time of theaudio data packet.

According to some embodiments, the processing circuitry 406 isconfigured to calculate a target synchronization value (e.g., a TXALIGNvalue having units of ms) using the calculated time delay. The timedelay between generation of an audio data frame and transmission of anaudio data packet is reduced by target synchronization value, but asmall non-zero time delay is preserved so that any delay in schedulingthe UL audio activities will not result in a delivery of audio data thatis later than the UL transmission time. Referring to the example shownin FIGS. 3A and 3B, the value of the target synchronization value is 10ms and the value of the preserved time delay is 2 ms. In someembodiments, statistics of the uplink is tracked and the value of thetarget synchronization value is calculated using the statistics. Forexample, the processing circuitry 460 may determine a central tendency(e.g., average) of the time delay over at least a portion of the 100samples shown in the example of FIGS. 3A and 3B and calculate the targetsynchronization value using the central tendency time delay. In certainvariations, statistics of the time delay may be collected over a slidingwindow of samples (e.g., (100-200 samples). In certain variations, thetime delay is determined by fixed network parameters.

Once the value of the target synchronization value is determined at thebeginning or during the phone call, it is desirable to adjust the delayduring operation of the device (e.g., on the fly) without requiring astop and restart of the UE or a reconfiguration of the UE. In someembodiments, the processing circuitry 406 initiates discarding of anumber of PCM samples equal to the target synchronization value todecrease the time delay. In the example of FIGS. 3A and 3B, the durationof a speech frame is 20 ms and includes a number of PCM samples. If 10ms of PCM samples are dropped, the time delay can be decreased from 12ms to 2 ms. The uplink capture of audio data is shifted by the number ofdropped PCM samples. Afterwards, PCM samples are read for the durationof a speech frame as usual and have the same periodicity.

When identifying PCM to be discarded, it is desired that PCM samplescorresponding to no speech activity (e.g., silence) during the call arethe PCM samples selected for discarding. In certain embodiments, theprocessing circuitry 406 may detect a PCM sample that corresponds to nospeech activity by determining that a detected level of energy in thePCM sample is less than a specified minimum energy level threshold. Theenergy level of a PCM sample may be less than a specified energy levelwhen the magnitudes of the digitized values are less than a thresholdmagnitude. In certain embodiments, the processing circuitry 406 maydetect a PCM sample that corresponds to no speech activity bydetermining that a number of zero-crossings in the PCM sample is greaterthan a specified zero-crossing threshold number.

According to some embodiments, if PCM samples corresponding to no speechactivity are not available, the synchronization by the discarding of PCMsamples is postponed to a future time when PCM samples corresponding tono speech activity are available. If no PCM samples corresponding to nospeech activity are available for a significant amount of time, thesynchronization may be forced by discarding PCM samples of speechactivity. In some embodiments, the processing circuitry 406 times aspecified timeout duration during the voice call and initiatesdiscarding of a specified number of PCM samples corresponding to speechactivity when PCM samples corresponding to no speech activity areundetected upon expiration of the timeout duration.

FIG. 5 illustrates another example of reducing delay in the uplink ofvoice information in radio access network. The delay is reduced byaligning the network uplink closer to the generation of the audio data.The example shows a sequence of events from right to left for the uplinkaudio processing chain. PCM samples are generated and placed in a PCMbuffer. In the example shown, a DSP may retrieve audio data every 5 ms.Depending on the implementation, the granularity of the data retrievalmay be 1 ms, 5 ms, 10 ms, or even 20 ms. A smaller granularity size mayimprove the alignment of the audio process with the network operation.The buffer size in the example is 40 ms or 8 samples of 5 ms. The topsequence 505 shows normal operation of the uplink process. The durationof a speech frame of the example is 20 ms, but the duration may dependon the implementation. A wakeup signal for uplink capture is generatedevery speech frame period.

The bottom sequence 510 shows operation to align the uplink with thegeneration of audio data. The target synchronization value has alreadybeen determined to be 10 ms. The object is to identify two samples of nospeech activity to match the target value of 10 ms and discard them.After the duration of a speech frame a number of samples correspondingto the target value (two samples in this example) are analyzed todetermine if they represent no speech activity. When the samples areidentified, a wakeup for the uplink capture is generated 10 ms earlier(the target synchronization value time) instead of at the speech frametime. Two PCM samples 512 and 514 are dropped. PCM samples are then readas usual. The result is that the uplink is aligned 10 ms closer to thedelivery the of audio data packet.

Additional opportunities for reducing the latency in end-to-end voicecommunications may be available depending on the communication protocolused by the radio access network. When new data is available in an LTEtype protocol (e.g., a third generation partnership project (3GPP) typeprotocol) a scheduling request (SR) is sent to the network to access therequired network resource. An On Duration is then timed that correspondsto a number of subframes at the start of a discontinuous reception (DRX)cycle. Following the On Duration is a period of possible inactivityduring which the new data may be transmitted. New data detection may beperformed by the MAC layer circuitry of the UE when data is receivedfrom the upper layers of the UE (e.g., from the audio subsystem). Uponreception of the new audio data, the MAC layer circuitry sends anindication to the PHY layer to transmit the SR to schedule the audiodata frame for transmission. Transmission of the audio data framefollows reception of an uplink (UL) grant from the network.

The uplink delay can be reduced by anticipating the arrival of new audiodata and sending the SR prior to the availability of new audio data.Determining the periodicity of the audio data allows the MAC layercircuitry to trigger the sending of the SR before the audio data isactually present at the MAC layer circuitry. The latency in end-to-endvoice communication is reduced by the amount of time between the sendingof the SR and the reception of the corresponding uplink (UL) grant.

FIG. 6 illustrates a timing diagram 600 of still another example ofreducing delay in the uplink of voice information in radio accessnetwork. The example relates to the timing of the automated sendingrequest of a VoLTE call. In the diagram, time flows from the top of FIG.6 to the bottom. The processing circuitry 406 of FIG. 4 may determinethe periodicity of new audio frames being generated by the audiosubsystem 609. The processing circuitry decreases the time durationbetween the generating of the audio data frame and a time slot scheduledfor the transmission of the audio data frame.

According to some embodiments, the time slot is scheduled according to aconnected discontinuous reception mode (C-DRX) with dynamic scheduling.In certain examples, the time slot is scheduled according to asemi-persistent scheduling (SPS) pattern. The time slot for transmissioncorresponds to an expected UL grant time. As shown in the example ofFIG. 6, the time duration is decreased by the cellular protocolspecification (CPS) triggering the SR 610 in anticipation of thedelivery of the audio frame packet 615 according to a real time protocol(RTP). In some embodiments, the MAC layer circuitry sends the indicationto the PHY layer circuitry to transmit a SR to schedule transmission ofthe audio data frame before the MAC layer circuitry receives the audioframe from the audio subsystem. In the example shown in FIG. 6, the MAClayer circuitry sends the indication to the PHY layer circuitry totransmit a SR to schedule transmission of the audio data frame beforethe audio subsystem generates the audio frame. Reducing the latency caninclude preserving a specified minimum time between delivery of theaudio frame packet 615 and the expected UL grant time.

In the case of audio silence (audio DTX) 625 during a voice call, noaudio data needs to be transmitted. The processing circuitry of the UEmay disable the sending of the SR prior to delivery of new audio data.As shown in FIG. 6, the SR is sent 630 to the network to access therequired resource after delivery 635 of the frame packet. When audioactivity is again detected 640, the early sending 645 of the SR inanticipation of new audio data is resumed. The advantage of sending anearly SR may depend on the network configuration. In certainembodiments, the early sending of SR is enabled according to the qualityof service of the UE, such as when the UE is used for internet protocolmultimedia system (IMS) for voice for example.

The several examples provided describe reduction in latency in a radioaccess network such as by voice over internet protocol (VoIP) forexample. The latency is reduced by reducing the delay in the uplink ofvoice data to the communication network. This can reduce the occurrenceof delay and echo during a voice call.

Additional Notes and Examples

Example 1 can include subject matter (such as a user equipment device)comprising physical layer circuitry configured to transmit and receiveradio frequency electrical signals with one or more nodes of a radioaccess network, an audio subsystem configured to generate frames ofaudio data, and processing circuitry. The processing circuitry isconfigured to calculate a time delay from generation of an audio dataframe by the audio subsystem of the UE device to transmission of anaudio data packet by the physical layer circuitry during a voice call,including a beginning of the voice call and when the voice call isactive, and to decrease the time delay to a delay value that preserves aspecified minimum time for delivery of the generated audio data frame tothe physical layer circuitry to meet a scheduled transmission time ofthe audio data packet.

In Example 2, the subject matter of Example 1 can optionally includeprocessing circuitry configured to initiate discarding of one or morePCM samples by the audio subsystem during the voice call to decrease thetime delay between the audio data frame generation and the transmissionof the audio data packet.

In Example 3, the subject matter of one or a combination of Examples1-2, can optionally include processing circuitry configured to detectone or more PCM samples corresponding to no speech activity and toinitiate discarding of one or more of the detected PCM samples.

In Example 4, the subject matter of one or any combination of Examples1-3 can optionally include processing circuitry configured to calculatea target synchronization value using the calculated time delay and toinitiate discarding of a number of PCM samples equal to the targetsynchronization value to decrease the time delay.

In Example 5, the subject matter of Example 4 can optionally includeprocessing circuitry configured to determine a central tendency timeperiod in which audio frames are generated by the audio subsystem andcalculate the target synchronization value using the central tendencytime period.

In Example 6, the subject matter of one or any combination of Examples1-5 can optionally include processing circuitry configured to time aspecified timeout duration during the voice call and initiate discardingof a specified number of PCM samples corresponding to speech activitywhen PCM samples corresponding to no speech activity are undetected uponexpiration of the timeout duration.

In Example 7, the subject matter of one or any combination of Examples1-6 can optionally include processing circuitry configured to decrease atime duration between the generating of the audio data frame and a timeslot scheduled for the transmission of the audio data frame.

In Example 8, the subject matter of Example 7 can optionally include thetime slot scheduled according to a connected discontinuous receptionmode (C-DRX) with dynamic scheduling, wherein the time slot correspondsto an expected uplink grant time.

In Example 9, the subject matter of one or any combination of Examples7-8 can optionally include the time slot scheduled according to asemi-persistent scheduling (SPS) pattern.

In Example 10, the subject matter of one or any combination of Examples7-9 can optionally include MAC layer circuitry configured to send anindication to the physical layer circuitry to transmit a schedulingrequest to schedule transmission of the audio data frame before the MAClayer circuitry receives the audio frame from the audio subsystem.

In Example 11, the subject matter of one or any combination of Examples7-10 can optionally include MAC layer circuitry configured to send anindication to the physical layer circuitry to transmit a schedulingrequest to schedule transmission of the audio data frame before theaudio subsystem generates the audio frame.

In Example 12, the subject matter of one or any combination of Examples1-11 can optionally include the radio network including a cellulartelephone network.

In Example 13, the subject matter of one or any combination of Examples1-12 can optionally include a UE configured to communicate data using atleast one of a voice over long term evolution (VoLTE) protocol or a highspeed downlink/uplink access (HSDPA/HSUPA) protocol.

Example 14 can include subject matter (such as a method, a means forperforming acts, or a machine-readable medium including instructionsthat, when performed by the machine, cause the machine to perform acts),or can optionally be combined with the subject matter of one or anycombination of Examples 1-13 to include such subject matter, comprisingcalculating a time delay from generation of an audio data frame by anaudio subsystem of the UE device to transmission of an audio data packetby a physical layer of the UE device during a voice call, including abeginning of the voice call and when the voice call is active, anddecreasing the time delay to a delay value that preserves a specifiedminimum time for delivery of the generated audio data frame to thephysical layer to meet a scheduled transmission time of the audio datapacket.

In Example 15, the subject matter of Example 14 can optionally includedecreasing the device delay includes discarding one or more pulse codemodulation (PCM) samples during the voice call to decrease the timedelay between the audio data frame generation and the transmission ofthe audio data packet.

In Example 16, the subject matter of Example 15 can optionally includedetecting one or more PCM samples corresponding to no speech activityand wherein discarding one or more PCM samples includes discarding thedetected one or more PCM samples.

In Example 17, the subject matter of one or a combination of Examples 15and 16 can optionally include calculating a target synchronization valueusing the calculated time delay, wherein discarding one or more PCMsamples includes discarding a number of PCM samples equal to the targetsynchronization value.

In Example 18, the subject matter of one or any combination of Examples14-17 can optionally include decreasing a time duration between thegenerating of the audio data frame and receiving an uplink (UL) grant.

In Example 19, the subject matter of one or any combination of Examples14-18 can optionally include decreasing a time duration between thegenerating of the audio data frame and a time slot corresponding to ascheduled UL grant of a specified radio pattern.

In Example 20, the subject matter of one or any combination of Examples14-19 can optionally include transmitting a scheduling request prior tothe audio subsystem generating an audio data frame to be transmittedafter receiving a requested UL grant.

Example 21 can include subject matter (such as a wireless communicationsystem), or can optionally be combined with the subject matter of one orany combination of Examples 1-20 to include such subject matter,comprising physical layer circuitry configured to transmit and receiveradio frequency electrical signals with one or more nodes of a radioaccess network, one or more antennas electrically coupled to thephysical layer circuitry, an audio subsystem configured to generateframes of audio data, and processing circuitry. The processing circuitryis configured to calculate a time delay from generation of an audio dataframe by the audio subsystem of the UE device to transmission of anaudio data packet by the physical layer circuitry during a voice call,including a beginning of the voice call and when the voice call isactive, and to decrease the time delay to a delay value that preserves aspecified minimum time for delivery of the generated audio data frame tothe physical layer circuitry to meet a scheduled transmission time ofthe audio data packet.

In Example 21, the subject matter of Example 20 can optionally includeprocessing circuitry configured to detect one or more pulse codemodulation (PCM) samples corresponding to no speech activity andinitiate discarding of the detected one or more PCM samples by the audiosubsystem during the voice call to decrease the time delay between theaudio data frame generation and the transmission of the audio datapacket.

In Example 22, the subject matter of one or a combination of Examples 20and 21 can optionally include processing circuitry configured tocalculate a target synchronization value using the calculated time delayand to initiate discarding of a number of the detected PCM samples equalto the target synchronization value.

In Example 23, the subject matter of one or any combination of Examples20-22 can optionally include processing circuitry configured tocalculate a target synchronization value using the calculated time delayand to initiate discarding of a number of the detected PCM samples equalto the target synchronization value.

In Example 24, the subject matter of one or any combination of Examples20-23 can optionally include processing circuitry configured to decreasea time duration between the generating of one or more audio data framesand receiving a user equipment uplink (UL) grant from the physical layercircuitry and to initiate the sending of a scheduling request by thephysical layer circuitry to schedule transmission of the audio dataframe before the audio subsystem generates the audio frame.

Example 25 can include subject matter, or can optionally be combinedwith the subject matter of one or any combination of Examples 1-24 toinclude such subject matter, such as a computer readable storage mediumincluding instructions that when performed by hardware processingcircuitry of a wireless communication device cause the wirelesscommunication device to: calculate a time delay from generation of anaudio data frame by an audio subsystem of the wireless communicationdevice to transmission of an audio data packet by a physical layer ofthe wireless communication device during a voice call, including abeginning of the voice call and when the voice call is active, anddecrease the time delay to a delay value that preserves a specifiedminimum time for delivery of the generated the audio data frame to thephysical layer to meet a scheduled transmission time of the audio datapacket.

In Example 26, the subject matter of Example 25 can optionally includeinstructions that when executed by the hardware processing circuitrycause the wireless communication device to detect one or more pulse codemodulation (PCM) samples corresponding to no speech activity and discardthe detected one or more PCM samples during the voice call to decreasethe device delay between the audio data frame generation and thetransmission of the audio data packet.

In Example 27, the subject matter of one or a combination of Examples25-26 can optionally include instructions that when executed by thehardware processing circuitry cause the wireless communication device tocalculate a target synchronization value using the calculated time delayand discard a number of PCM samples equal to the target synchronizationvalue.

In Example 28, the subject matter of one or any combination of Examples25-27 can optionally include instructions that when executed by thehardware processing circuitry cause the wireless communication device tosend a scheduling request to the physical layer to transmit an audioframe prior to the audio subsystem generating the audio frame.

These non-limiting examples can be combined in any permutation orcombination.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” All publications, patents, and patent documentsreferred to in this document are incorporated by reference herein intheir entirety, as though individually incorporated by reference. In theevent of inconsistent usages between this document and those documentsso incorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable storagemedium or machine-readable storage medium encoded with instructionsoperable to configure an electronic device to perform methods asdescribed in the above examples. An implementation of such methods caninclude code, such as microcode, assembly language code, a higher-levellanguage code, or the like. Such code can include computer readableinstructions for performing various methods. The code may form portionsof computer program products. The code can be tangibly stored on one ormore volatile, non-transitory, or non-volatile tangiblecomputer-readable media, such as during execution or at other times.Examples of these tangible computer-readable storage media can include,but are not limited to, hard disks, removable magnetic disks, removableoptical disks (e.g., compact disks and digital video disks), magneticcassettes, memory cards or sticks, random access memories (RAMs), readonly memories (ROMs), and the like.

The Abstract is provided to comply with 37 C.F.R. Section 1.72(b)requiring an abstract that will allow the reader to ascertain the natureand gist of the technical disclosure. It is submitted with theunderstanding that it will not be used to limit or interpret the scopeor meaning of the claims. The following claims are hereby incorporatedinto the detailed description, with each claim standing on its own as aseparate embodiment. Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, or process that includes elements in addition to those listedafter such a term in a claim are still deemed to fall within the scopeof that claim. Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects.

What is claimed is:
 1. A user equipment device (UE) comprising: physicallayer circuitry configured to transmit and receive radio frequencyelectrical signals with one or more nodes of a radio access network; anaudio subsystem configured to generate frames of audio data; andprocessing circuitry configured to: calculate a time delay fromgeneration of an audio data frame by the audio subsystem of the UEdevice to transmission of an audio data packet by the physical layercircuitry during a voice call, including a beginning of the voice calland when the voice call is active; and decrease the time delay to adelay value that preserves a specified minimum time for delivery of thegenerated audio data frame to the physical layer circuitry to meet ascheduled transmission time of the audio data packet.
 2. The UE of claim1, wherein the processing circuitry is configured to initiate discardingof one or more pulse code modulation (PCM) samples by the audiosubsystem during the voice call to decrease the time delay between theaudio data frame generation and the transmission of the audio datapacket.
 3. The UE of claim 2, wherein the processing circuitry isconfigured to detect one or more PCM samples corresponding to no speechactivity and to initiate discarding of one or more of the detected PCMsamples.
 4. The UE of claim 2, wherein the processing circuitry isconfigured to calculate a target synchronization value using thecalculated time delay and to initiate discarding of a number of PCMsamples equal to the target synchronization value to decrease the timedelay.
 5. The UE of claim 4, wherein the processing circuitry isconfigured to determine a central tendency time period in which audioframes are generated by the audio subsystem and calculate the targetsynchronization value using the central tendency time period.
 6. The UEof claim 2, wherein the processing circuitry is configured to time aspecified timeout duration during the voice call and initiate discardingof a specified number of PCM samples corresponding to speech activitywhen PCM samples corresponding to no speech activity are undetected uponexpiration of the timeout duration.
 7. The UE of claim 1, wherein theprocessing circuitry is configured to decrease a time duration betweenthe generating of the audio data frame and a time slot scheduled for thetransmission of the audio data frame.
 8. The UE of claim 7, wherein thetime slot is scheduled according to a connected discontinuous receptionmode (C-DRX) with dynamic scheduling, wherein the time slot correspondsto an expected uplink grant time.
 9. The UE of claim 7, wherein the timeslot is scheduled according to a semi-persistent scheduling (SPS)pattern.
 10. The UE of claim 7, including MAC layer circuitry configuredto send an indication to the physical layer circuitry to transmit ascheduling request to schedule transmission of the audio data framebefore the MAC layer circuitry receives the audio frame from the audiosubsystem.
 11. The UE of claim 7, including MAC layer circuitryconfigured to send an indication to the physical layer circuitry totransmit a scheduling request to schedule transmission of the audio dataframe before the audio subsystem generates the audio frame.
 12. The UEof claim 1, wherein the radio network includes a cellular telephonenetwork.
 13. The UE of claim 12, wherein the UE is configured tocommunicate data using at least one of a voice over long term evolution(VoLTE) protocol or a high speed downlink/uplink access (HSDPA/HSUPA)protocol.
 14. A method of operating a UE device of an end-to-endcommunication network, the method comprising: calculating a time delayfrom generation of an audio data frame by an audio subsystem of the UEdevice to transmission of an audio data packet by a physical layer ofthe UE device during a voice call, including a beginning of the voicecall and when the voice call is active; and decreasing the time delay toa delay value that preserves a specified minimum time for delivery ofthe generated audio data frame to the physical layer to meet a scheduledtransmission time of the audio data packet.
 15. The method of claim 14,including detecting one or more pulse code modulation (PCM) samplescorresponding to no speech activity and wherein decreasing the devicedelay includes discarding the detected one or more PCM samples duringthe voice call to decrease the time delay between the audio data framegeneration and the transmission of the audio data packet.
 16. The methodof claim 14, wherein decreasing the time delay includes decreasing atime duration between the generating of the audio data frame andreceiving an uplink (UL) grant.
 17. The method of claim 14, whereindecreasing the time delay includes decreasing a time duration betweenthe generating of the audio data frame and a time slot corresponding toa scheduled UL grant of a specified radio pattern.
 18. The method ofclaim 14, wherein decreasing the time delay includes transmitting ascheduling request prior to the audio subsystem generating an audio dataframe to be transmitted after receiving a requested UL grant.
 19. Awireless communication system comprising: physical layer circuitryconfigured to transmit and receive radio frequency electrical signalswith one or more nodes of a radio access network; one or more antennaselectrically coupled to the physical layer circuitry; an audio subsystemconfigured to generate frames of audio data; processing circuitryconfigured to: calculate a time delay from generation of an audio dataframe by the audio subsystem to transmission of an audio data packet bythe physical layer circuitry during a voice call, including a beginningof the voice call and when the voice call is active; and decrease thetime delay to a delay value that preserves a specified minimum time fordelivery of the generated audio data frame to the physical layercircuitry to meet a scheduled transmission time of the audio datapacket.
 20. The wireless communication system of claim 19, wherein theprocessing circuitry is configured to detect one or more pulse codemodulation (PCM) samples corresponding to no speech activity andinitiate discarding of the detected one or more PCM samples by the audiosubsystem during the voice call to decrease the time delay between theaudio data frame generation and the transmission of the audio datapacket.
 21. The wireless communication system of claim 20, wherein theprocessing circuitry is configured to calculate a target synchronizationvalue using the calculated time delay and to initiate discarding of anumber of the detected PCM samples equal to the target synchronizationvalue.
 22. The wireless communication system of claim 19, wherein theprocessing circuitry is configured to decrease a time duration betweenthe generating of one or more audio data frames and receiving a userequipment uplink (UL) grant from the physical layer circuitry and toinitiate the sending of a scheduling request by the physical layercircuitry to schedule transmission of the audio data frame before theaudio subsystem generates the audio frame.
 23. A computer readablestorage medium including instructions that when executed by hardwareprocessing circuitry of a wireless communication device cause thewireless communication device to: calculate a time delay from generationof an audio data frame by an audio subsystem of the wirelesscommunication device to transmission of an audio data packet by aphysical layer of the wireless communication device during a voice call,including a beginning of the voice call and when the voice call isactive; and decrease the time delay to a delay value that preserves aspecified minimum time for delivery of the generated the audio dataframe to the physical layer to meet a scheduled transmission time of theaudio data packet.
 24. The computer readable storage medium of claim 23,including instructions that when executed by the hardware processingcircuitry cause the wireless communication device to detect one or morepulse code modulation (PCM) samples corresponding to no speech activityand discard the detected one or more PCM samples during the voice callto decrease the device delay between the audio data frame generation andthe transmission of the audio data packet.
 25. The computer readablestorage medium of claim 23, including instructions that when executed bythe hardware processing circuitry cause the wireless communicationdevice to send a scheduling request to the physical layer to transmit anaudio frame prior to the audio subsystem generating the audio frame.